Gas-barrier coated films, sheets or foils and method of preparation

Abstract

Films, sheets or foils are given a gas-barrier coating of an aromatic polyamide, polyimide, polyamide-imide, polyhydrazide, polyamide-hydrazide, or polyazomethine by direct vapor-phase condensation polymerization of their respective monomers. The monomers are introduced in an inert diluent gas, mixed and reacted in the presence of the surface to be coated. The surface is maintained above the critical minimum deposition temperature of the monomers but below about 300° C. The coating is formed to a thickness between about 0.1 and 0.6 mil.

We claim: 
     
       1. A process for forming a gas-barrier coating on a film, sheet or foil, said coating being an aromatic polyamide, polyimide, polyamide-imide, polyhydrazide, polyamidehydrazide or polyazomethine formed by the direct vapor-phase condensation polymerization of their respective monomers, which process comprises vaporizing said monomers, mixing said vaporized monomers in the presence of an inert diluent gas and reacting said mixed monomers in a reaction zone, in the presence of said film, sheet or foil maintained above the critical minimum deposition temperature of said monomers but below about 300° C., and forming the condensation polymer on the surface of said film to a thickness between about 0.01 and about 0.6 mil. 
     
     
       2. The process defined in claim 1 wherein said coating is between about 0.05 and about 0.2 mil in thickness. 
     
     
       3. The process defined in claim 1 wherein said coating is an aromatic polyamide and said film, sheet or foil is maintained at a temperature between about 160° and 300° C. 
     
     
       4. The process defined in claim 3 wherein said monomers are p-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       5. The process defined in claim 3 wherein said monomers are m-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       6. The process defined in claim 3 wherein said monomers are m-phenylene diamine and the diacid chloride of isophthalic acid. 
     
     
       7. The process defined in claim 6 wherein the diacid chloride of isophthalic acid is present in mixture with the diacid chloride of terephthalic acid. 
     
     
       8. The process as defined in claim 3 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyester film. 
     
     
       9. The process as defined in claim 8 wherein said polyester film is polyethylene terephthalate film and said monomers are p-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       10. The process as defined in claim 1 wherein said coating is an aromatic polyimide. 
     
     
       11. The process as defined in claim 10 wherein said film, sheet or foil is maintained at a temperature between about 120° C. and 200° C. and the condensation polymer formed on the surface is the polyamic acid which is subsequently heated to convert it to the polyimide. 
     
     
       12. The process as defined in claim 10 wherein said film, sheet or foil is maintained at a temperature between about 200° C. and 300° C. 
     
     
       13. The process as defined in claim 10 wherein said monomers are 4,4'-diaminodiphenyl ether and pyromellitic dianhydride. 
     
     
       14. The process as defined in claim 10 wherein the monomers are p-phenylene diamine and pyromellitic dianhydride. 
     
     
       15. The process as defined in claim 1 wherein said coating is an aromatic polyamide-imide. 
     
     
       16. The process as defined in claim 15 wherein said film, sheet or foil is maintained at a temperature between about 140° C. and 200° C. and the condensation polymer formed on the surface is the polyamide-amic acid which is subsequently heated to convert it to the polyamide-imide. 
     
     
       17. The process as defined in claim 15 wherein said film, sheet or foil is maintained at a temperature between about 200° C. and 300° C. 
     
     
       18. The process as defined in claim 15 wherein said monomers are 4,4'-diaminodiphenyl ether and trimellitic anhydride monoacid chloride. 
     
     
       19. The process as defined in claim 15 wherein said monomers are p-phenylene diamine and trimellitic anhydride monoacid chloride. 
     
     
       20. The process as defined in claim 1 wherein said coating is an aromatic polyhydrazide and said film, sheet or foil is maintained at a temperature between about 120° C. and 300° C. 
     
     
       21. The process as defined in claim 20 wherein said monomers are the hydrazide of isophthalic acid and the diacid chloride of terephthalic acid. 
     
     
       22. The process as defined in claim 1 wherein said coating is an aromatic polyamide-hydrazide and said film, sheet or foil is maintained at a temperature between about 100° C. and 300° C. 
     
     
       23. The process as defined in claim 22 wherein said monomers are p-aminobenzhydrazide and the diacid chloride of terephthalic acid. 
     
     
       24. The process as defined in claim 23 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyethylene terephthalate film. 
     
     
       25. The process as defined in claim 1 wherein said coating is an aromatic polyazomethine and said film, sheet or foil is maintained at a temperature between about 100° C. and 300° C. 
     
     
       26. The process as defined in claim 25 wherein said monomers are p-phenylene diamine and terephthalyl aldehyde. 
     
     
       27. The process as defined in claim 26 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyethylene terephthalate film. 
     
     
       28. A film, sheet or foil having a gas-barrier coating thereon of an aromatic polyamide, polyimide, polyamide-imide, polyhydrazide, polyamide-hydrazide or polyazomethine formed onto said film by the direct vapor-phase condensation polymerization of their respective monomers mixed in the vapor state and reacted in the presence of said film, sheet or foil maintained above the critical minimum deposition temperature of said monomers but below about 300° C., said coating having a thickness between about 0.01 and about 0.6 mil. 
     
     
       29. A film, sheet or foil as defined in claim 28 wherein said coating is between about 0.05 and about 0.2 mil in thickness. 
     
     
       30. A film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyamide and said film, sheet or foil is maintained at a temperature between about 160° C. and 300° C. 
     
     
       31. A film, sheet or foil as defined in claim 30 wherein said monomers are p-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       32. The film, sheet or foil as defined in claim 30 wherein said monomers are m-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       33. The film, sheet or foil as defined in claim 30 wherein said monomers are m-phenylene diamine and the diacid chloride of isophthalic acid. 
     
     
       34. The film, sheet or foil as defined in claim 33 wherein the diacid chloride of isophthalic acid is present in mixture with the diacid chloride of terephthalic acid. 
     
     
       35. The film, sheet or foil as defined in claim 30 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyester film. 
     
     
       36. The film, sheet or foil as defined in claim 35 wherein said polyester is polyethylene terephthalate and said monomers are p-phenylene diamine and the diacid chloride of terephthalic acid. 
     
     
       37. The film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyimide. 
     
     
       38. The film, sheet or foil as defined in claim 37 wherein said film, sheet or foil is maintained at a temperature between about 120° C. and 200° C. and the condensation polymer formed on the surface is the polyamic acid which is subsequently heated to convert it to the polyimide. 
     
     
       39. The film, sheet or foil as defined in claim 37 wherein said film, sheet or foil is maintained at a temperature between about 200° C. and 300° C. 
     
     
       40. The film, sheet or foil as defined in claim 37 wherein said monomers are 4,4'-diaminodiphenyl ether and pyromellitic dianhydride. 
     
     
       41. The film, sheet or foil as in claim 37 wherein the monomers are p-phenylene diamine and pyromellitic dianhydride. 
     
     
       42. The film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyamide-imide. 
     
     
       43. The film, sheet or foil as defined in claim 42 wherein said film, sheet or foil is maintained at a temperature between about 140° C. and 200° C. and the condensation polymer formed on the surface is the polyamide-amic acid which is subsequently heated to convert it to the polyamide-imide. 
     
     
       44. The film, sheet or foil as defined in claim 42 wherein said film, sheet or foil is maintained at a temperature between about 200° C. and 300° C. 
     
     
       45. The film, sheet or foil as defined in claim 42 wherein said monomers are 4,4'-diaminodiphenyl ether and trimellitic anhydride monoacid chloride. 
     
     
       46. The film, sheet or foil as defined in claim 42 wherein said monomers are p-phenylene diamine and trimellitic anhydride monoacid chloride. 
     
     
       47. The film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyhydrazide and said film, sheet or foil is maintained at a temperature between about 120° C. and 300° C. 
     
     
       48. The film, sheet or foil as defined in claim 47 wherein said monomers are the hydrazide of isophthalic acid and the diacid chloride of terephthalic acid. 
     
     
       49. An organic polymeric film having a gas-barrier coating thereon of an aromatic polyamide consisting essentially of units p-phenylene diamine and terephthalic acid having a density greater than about 1.42, a planar X-ray orientation and an electron microscope morphology of a coalesced particulate texture. 
     
     
       50. The film as defined in claim 49 wherein the polymeric film is a polyimide film or a biaxially oriented, heat-set polyethylene terephthalate film. 
     
     
       51. A film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyamide-hydrazide and said film, sheet or foil is maintained at a temperature between about 100° C. and 300° C. 
     
     
       52. A film, sheet or foil as defined in claim 51 wherein said monomers are p-aminobenzhydrazide and the diacid chloride of terephthalic acid. 
     
     
       53. The film, sheet or foil as defined in claim 52 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyethylene terephthalate film. 
     
     
       54. A film, sheet or foil as defined in claim 28 wherein said coating is an aromatic polyazomethine and said film, sheet or foil is maintained at a temperature between about 100° C. and 300° C. 
     
     
       55. A film, sheet or foil as defined in claim 54 wherein said monomers are p-phenylene diamine and terephthalyl aldehyde. 
     
     
       56. A film, sheet or foil as defined in claim 55 wherein said film, sheet or foil is a polyimide film or a biaxially oriented, heat-set polyethylene terephthalate film. 
     
     
       57. A substrate having a coating thereon of a polymer selected from the group consisting of aromatic polyamide, polyimide, polyamide-imide, polyhydrazide, polyamide-hydrazide and polyazomethine formed onto said substrate by the direct vapor-phase condensation polymerization of said polymer's respective monomers mixed in the vapor state and reacted in the presence of said substrate maintained above the critical minimum deposition temperature of said monomers but below about 300° C., said coating having a thickness between about 0.01 and about 0.6 mil.